Resistance element.



H. P. BALL;

RESISTANCE ELEMENT.

A'PPLICATION FILED APR- 9; i914.

1442x173. Patented A112. 10. 1915.

- Inn If Fig.2.

Witnesses: E Y In\ /entor-: Q fad 9 41 5 t Henry F! B rr,

His fitt orneg UNITED STATES PATENT OFFICE.

HENRY PRICE BALL, OLE PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RESISTANCE ELEMENT.

o i i 1 li ti n filed August 6, 1909, Serial No. 511,521. Divided and this application filed April 9,

SerialNo. 830,595.

To all whom it may concern Be it known that I, HENRY PRICE BALL, a citizen of the United States, residing at littsfield, county of Berkshire, State of lVIassachusetts, have invented certain new and useful Improvements in Resistance Ele ments, of which the following is a specification. I

My present invention relates to a resistance unit or element and the method of manufacturing the same and has for its object the provision of a simple and eflicient unit which is well adapted for use in flatirons or other heating devices.

This applicationis a division of my prior application, Serial No. 511,521, filed August 6, 1909. In that application I have'dlsclosed a fiatiron in which the resistance unit is cast in the body of the iron.

My present application relates to the form I of resistance unit described in my prior application. The unit is formed of zigzag resistance conductors laid between strips of insulating material and incloscd in a flattened tube. Insulating men'ibers are provided to prevent the conductors from'contacting with the tube and the tube is flattened so as to compress the members tightly.

In the accompanying drawings, Figure l is a sectional View of a fiatiron embodying my invention; Fig. 2 is a plan view of the bottom portion of the iron; and Fig. 3 is a perspective view of the heating unit which is covered by my present invention.

Referring to the drawings, 10 represents the body portion having a heating unit 11 cast therein. This unit is formed of a flat strip and is cast on edge, that is, it stands in the body of the iron' in a plane perpendicular to the plane of the iron and also in a plane perpendicular to the plane of greatest contraction in cooling. The unit is preferably looped or .reflexed, as shown in Fig. 2, to enable as much of the unit as possible to run transversely to the longitudinal length of the iron, as I find the iron shrinks greater lengthwise than crosswise, and this subjects the sides of the unit to enormous pressure, when the cast iron bears down upon it. The reflexing a'ls'oprevents any tendency on the part of the sides of the flattened tube to open up due to mechanical strain. It also locks the mica or other insulation inside the tube so that it cannot shift. The unit itself con- Specification of Letters Patent.

sists of a. Zigzag resistance conductor 12,

which may be formed in any desired manner, as for instance, by punching it out of sheet metal. The material out of which this is formed is preferably of high resistance and non-oxidizable. I have found that the resistance metal disclosed in the patent to Dempster 901,128 is .very suitable for this purpose. The resistance conductor is zigzagged so as to form a strip, and is laid between two strips of insulating material 13, such, for instance, as mica, and insulating members 14, which may also beef mica, are secured between the sections of the conductor, as shown in Fig. 3. These insulating members are placed at intervals along the conductor to prevent the conductor from contacting withthe inclosing casing. The resistance conductor with its mica strips is then inclosed in a flat tube, as shown in Fig. 3. The tube is flattened to the form necessary, and may then be further flattened so as to compress the members tightly.

While I have described my invention as embodied in concrete form for purposes of illustration, it should be understood that I do-not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

\Vhat I claim as new and desire to care by Letters Patent of the United States, is:

1. A resistance element comprising a heatconducting sheath having a continuous unbroken outer surface and an insulated high resistance conductor maintained at a minimum thickness within said sheath by the walls thereof.

A resistance element comprising a heat conducting sheath having a continuous unbroken outer surface and an insulated high resistance conducting ribbon inclosed within said sheath and maintained at a minimum thickness by the walls thereof.

3. A resistance element comprising a heat conducting sheath having a continuous unbroken outer surface and an insulated high resistance conducting ribbon having a plurality of lateral slots cut alternately in 0pposite edges to form a zig-zag current conducting path therethrough and maintained 5. The method of forming an electrical heater element which consists in threading 10 an msulated conductor through a metal tube and then applying sufiicient pressure to said. tube to reduce the same to a minimum thiclv ness.

In witness whereof, I have hereunto set my hand this -l-th day of April 1914.

HENRY PRICE BALL.

\Vitnesses H. B. DAVERIN, M. J. RurxoLns. 

